The invention relates to a device for guiding a drilling tool for forming a second bore in a bone, which second bore intersects an already existing first bore.
A device for guiding a drilling tool and having these design features is known from U.S. Pat. No. 6,540,783 B1.
Such a device is used for fixing a tendon replacement fitted in a bone, mostly in the area of the knee joint.
For this purpose, a drilling tool is used to form a first bore in the bone, said bore extending both through the thigh bone (femur) and also through the shin bone (tibia). A tendon replacement is pushed into this first bore.
To fix this tendon replacement, a transverse pin is introduced which is driven transversely into the tendon replacement or into a loop in the tendon replacement, such that the tendon replacement is fixed by this transverse pin against being pulled out of the first bore.
To introduce the transverse pin, it is necessary to produce an additional second bore in the thigh bone, said second bore being oriented such that it intersects the first bore, that is to say extends transversely, mostly at right angles, with respect to the latter.
Since, from this transverse direction, the position of the first bore in the bone is not visible to the operator, auxiliary devices or sighting devices have been created with which this second bore extending transversely with respect to the first bore can be arranged precisely in the correct position for introduction of the transverse pin, i.e. in such a way that this second bore meets the first bore.
The aforementioned device known from U.S. Pat. No. 6,540,783 B1 has an L-shaped frame at whose first end a rod-shaped sleeve is arranged through which a guide wire can be guided, which can be inserted into the already existing bore in the femur and the tibia. At the second end of the L-shaped frame there is a guide element comprising two through-openings.
When producing a second bore in the bone that extends transversely with respect to the first bore, the guide wire received in the sleeve is first introduced into the first bore in the tibia and the femur. A guide sleeve that serves to receive a trocar or a drilling tool is pushed into each of the openings in the guide element. After a trocar has been inserted into the two guide sleeves in each case, the guide sleeves, with the trocars received in the sleeves, are driven into the femur, specifically such that the tips of the trocars do not yet extend into the first bore in the bone.
Thereafter, both the L-shaped frame and also the sleeve arranged at the first end of the frame are pulled off with the guide wire, and the tendon replacement is pushed into the first bore. The two trocars with the guide sleeves are then driven further into the femur, such that the tendon replacement located in the first bore is pierced by them. The trocars are then removed, and two transverse pins are introduced through the guide sleeves remaining in the second bores in order to secure the tendon replacement against being pulled out of the first bore in the bone.
In order to introduce the transverse pins precisely into the respective second bore in the bone using this device, it is necessary that the two guide sleeves are inserted into the bone of the patient and initially remain in the bone, especially after the L-shaped frame and the sleeve have been drawn off with the guide wire.
After the transverse pins have been introduced into the second bore, the guide sleeves still present in the second bore have to be removed from the bone.
However, this proves to be a disadvantage, because removing the guide sleeves can cause a change of position of the transverse pins introduced into the second bore.
In the bone, the guide sleeves cause a channel which is quite a bit larger than is necessary for insertion of the transverse pin. Moreover, since two such channels are produced, there is an unnecessarily high degree of excavation and, consequently, a weakening of the bone in this area. If revision surgery had to be performed later, relatively large areas of the bone would already be weakened by the two channels.
It is therefore an object of the present invention to develop a device of the type mentioned at the outset in such a way that the transverse pin can be introduced and precisely positioned without causing unnecessary trauma to the bone substance.